甘蓝型油菜角果光合日变化特性的研究

Study on Diurnal Changes of Photosynthetic Characteristics in Pods of Brassica napus

用LI-6400光合作用测定系统对4个甘蓝型杂交油菜品种角果的光合、蒸腾及水分利用效率等的日变化进行了研究,结果表明:油菜角果净光合速率(Pn)的日变化呈双峰曲线,两个峰值相差39.173%,上午的Pn平均比下午高25.694%,有明显的"光合午休"现象,"光合午休"产生的原因主要是由于气孔因素限制;蒸腾速率的日变化也为双峰曲线、中午前后有明显的降低,但两个峰值相差仅4.731%,峰值出现的时间也相对推后,下午蒸腾速率平均比上午高33.983;水分利用效率的日变化曲线为非典型的双峰曲线,不同品种之间有很大差别;本文还对引起角果净光合速率、蒸腾速率、水分利用效率和气孔导度等产生日变化的因素进行了相关分析。

On a fine day,photosynthetic characteristics in pods of four hybrid lines of Brassica napus were analyzed by using portable LI-6400 photosynthesis system.The result showed that the diurnal changes in net photosynthetic rate（Pn） of pods were ＂two-peak curve＂,and the first peak at 11：00 were higher 39.173% than the second peak at 16：00,the average Pn value in the morning（9：00～11：00） was higher 25.694% than the value in the afternoon（15：00～17：00）,there were obviously appearance of photosynthetic midday depression at noon.With the decline of stomata conductance to H2O（Cond） and CO2 concentration at intercellular spaces（Ci）,and the raise of limitation of stomata（Ls）,Pn declined distinctly in midday,so this means that Pn was limited by the stomata factor.The curves of transpiration rate（Trm）were also ＂two-peak curve＂ as the Pn＇s curve of diurnal changes,but the time reaching the peaks and the valleys were latter than the Pn＇s.The difference between the first peak and the second one was 4.731%,the average Trm value in the afternoon was higher 33.983% than the average Trm value in the morning,The curves of diurnal changes of water use efficiency（Wue） were ＂non-typical two-peak curves＂,there were significant difference among the four hybrid lines.The partial correlation relationship among the physiological parameters,such as Pn,Trm,Cond and Wue in pods were analyzed by using the SPSS analysis system.